<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        let obj = {
            state: Symbol()
        };
        function show(str){
            if(str === obj.state){
                return "升序";
            }else{
                return "降序";
            }
        }

//        alert(show(obj.state));
        alert(show("up"));
    </script>
</head>
<body>

</body>
</html>